Carburetor device



May 30, 1939- v A. H. BLATTNER 2,160,410

GARBURETOR DEvIca @y Mali@ May 30;v 1939- A. H. BLATTNl-:R 'I 2,160,410

OARBURETOR DEVICE `Filed June 2, 1956 4 Sheets-Shea?I 2 May 30, 1939. A.H. BLATTNER CAEBURITOR DEVIB 4 Sheets-Sheet 5 Filed June 2, 1936Patented May 30, 1939 vCARBURETOR DEVICE August H. Blattner, St. Louis,Mo.,v assignor to Carter Carburetor Corporation, St. Louis, Mo., acorporation of Delaware Application June 2, 1936, Serial No. 83,066

Claims. This invention relates to earburetors for internal combustionengines and consists particularly in novel interconnection control meansextending between the choke and throttle valves. 5' Inautomatic chokecarburetors, it is desirable to provide manual means for modifying theposition of the choke valve as otherwise determined by thermostaticand/or suction control devices and also means for varying the limitingposition to which the throttle valve may be moved either manually or bymeans of the usual closing spring.

When the engine is cold, the choke valve in an automatic chokecarburetorismaintained substantially closed by the thermostat so as toprovide maximum suction on the fuel nozzles during the cranking andwarming periods. Occasionally an over-rich mixture is furnished to thecylin ders before the choke valve has opened substantially, due, forinstance, to -excessive charges from the accelerating pump caused byrepeated deprsing of the throttle pedal or to sticking of the chokevalve. 'I'his loading" may be eliminated if the choke valve is quicklyopened,

the resulting gust of air serving to clean out the g5 intake system.

When the thermostat becomes heated, the

choke valve is held thereby in its full open position so as toconstitute a minimum restriction in the air inlet. Occasionally, whenthe choke and l0 throttle valves are fully open, as, for instance, whena warm engine is subjected to a heavy load and the atmosphere is cold,there may be a tendency for the choke valve to close slightly, causing'an undesirable enriching of the mixture.

35 This is due to the low suction in the intake manifold, which isrelied upon to draw heated air into the vicinity of the thermostat. Itis thus desirable to lock the choke valve in its full open position whenthe throttle is substantially fully open.

- 40 The throttle valve is normally urged toward its fully closedposition by a spring, but during the warm-up period, the engine oil andgrease may be abnormally viscous, particularly in cold weather,

u and for this and other reasons, it is desirable that the idling speedof theengine be automatically accelerated during this period to preventstalling.

Fast idle and unloading devices have heretofore been providedjbut thesehave been relatively 5d complicated, unsightly, and expensive tomanufacture, or not adaptable to automatic chokes.

An object of the present invention is to provide novel, simplifiedinterconnecting means for ca-bure tor throttle and choke valves.

Another object is to provide means for locking the choke valve in itsfull open position when the throttle valve is substantially fully open.

Another object is to provide a choke and throttle interconnection formedsubstantially of a single linkage arrangement incorporating fast 5 idleand unloading features, and means for locking the choke open when boththe choke and throttle valves are fully open.

Another object. is to provide a'fast idle device having an adjustableunloadingv element formed l0 as a part thereof.

'I'hese objects and other more detailed objects hereafter appearing areattained by the present invention which is characterized substantiallyby the provision of a fast idle block slidably mount- 15 ed adjacent thethrottle operating lever and having an adjustable, curved, unloading lipfor cooperating 4with the throttle lever to open the choke whenthethrottle is opened to a predetermined extent. motion connection witha control lever rigid with the choke valve. 'I'he choke lever has alateral extension positioned to overlie the upper extremity of the linkwhen the choke and throttle are substantially fully open so as to lockthe choke. i

In the accompanying drawings:

Figure 1 is a side view of a carburetor embodying the invention, 'thevalves being shown in the unloading positions.

Figure 2 is'a diagrammatic view showing the choke and throttle valvesand inter-connection linkage. A

Figure 3 is a view 'similarv to Figure 1, but

showing the linkage and valves in aldiiferent position, portions of thecarburetor :being broken away.

Figure 4 is a diagrammatic view showing the linkage and valv in anotherposition.'

Figure 5 is a view similar to Figure 3, but show- 40 ing the choke andthrottle valves fully opened, and f Figure 6 is a view ofthe carburetortaken at 90 degrees to Figuresl, 3V and 5, part. of the structure beingbroken away.

The carburetor illustrated is of the downdraft type including an airinlet horn l, a mixing chamber 2, and mixture outlet 3 anged as at l forattachment to an engine manifold (not shown). Located in the mixturepassageare a series of venturis 5, and a main fuel nozzle .6 openinginto the interior of smallest or primary venturi.- An unbalanced chokevalve 'I is mounted on pivot 8 Iin the air horn and a throttle valve 9is mounted on pivot I0 between the mix- The fast idle block has a lostA20 I ing chamber and the mixture outlet. A crank I I is provided formanually controlling the throttle valve.

Mounted on the outside of the air horn is a housing I2 enclosing aVspiral, bi-metallic thermostat I3, the inner portion of which is securedto the choke valve pivot 8. The outer end of the thermostat may beanchored to the cover portion of the housing I 2 -and the tension on thethermostat 4may be varied by the rotation of the cover. A threadednipple I4 provides for connecting the 'thermostat housing with a sourceof hot air, and suction means preferably will be provided for drawinghot air from a stove 35, conveniently mounted on vthe engine exhaustmanifold 36, through the thermostat housing. The suction means fordrawing hot air from the stove 35 may be of any conventional form,however, the pipe 31 is indicated for suitable connection to anyconventional source of connection such as the intake manifold.

Formed-integral with the carburetor body isa fuel bowl I5 in which islocated an accelerating pump generally indicated at I9 for spraying rawfuel into the mixing chamber through nozzle I1 when the. throttle isopened.

A rib I8 projecting from the carburetor body adjacent throttle lever IIslidably mounts the slotted fast idle block I9 by means of a -pair ofscrews 20. The fast idle block has a curved lip 2l which may beconveniently formed of a section of metal bent away from the slottedbody portion of the block.` Block I9 is pivoted, as at 2'Ia, toa link 22having a slot 23 in its upper portion loosely receiving a pin abutment24 projecting laterally from the control arm 25 rigidly mounted on the'choke pivot 8 between the air horn I and housing I2. Choke lever 25 hasa laterally projectinglip abutment 26 at its outer extremity which isadapted to lie above the nub 21 on the upper end of link 22 when boththe choke and throttle are' full open." A wlrespring 28 secured to link22 as at 29, bears against choke lever pin 24 and constantly urges thesame against the inner portion of slot 23. The loose'fit between slot 23and pin 24, and spring 29 cooperate t to cause nub 21 to lle wellbeneath lip 26 in the locked position, as in Fig. 5.

The operation of the device is as follows: The starting positions of thevalves are indicated in Fig. 2 in which the choke is held closed by acold thermostat, and the throttle is partially opened to the positionwherein throttle crank II just touches but does not raise lip 2l onblock I9. 'I'he fast idle block I9 is in -the lowest position, supportedby top screw 2l, so as to be engaged bythrottle screw 32 duringclockwise movement of crank II, to limit closing movement of thethrottle to the fast idle `position (Fig. 4). With block I9 held betweenrib I9 and screw 32, block 23 Vpermits e opening or breathing of thechoke valve, to the extent indicated in Fig. 4, to provide sufficientair during the cranking and warm up periods.

In lcase the mixture supplied during the warm up should become over-richor the engine become loaded for any reason, the choke valve may bemanually forced to a partially open position, as

indicated in Fig. 1, by moving the throttle lever II in 'acounter-clockwise direction beyond the position shown' in Fig. 2 so ast-o cause the cam surface 30 on lever II to lift curved lip 2| andvlinkage elements I9, 22, whereupon the bottom of slot 23 serves as anabutment to engage and rotate pin 24 and open the choke valve. Thiscauses a gust ofair to pass through the carburetor, cleaning out orunloading the intake system. For unloading, the throttle valve need beopened only momentarily. When the throttle is released to be moved bythe usual return spring (not shown) to the idling position, block I9drops and the choke valve closes as determined by the thermostat. BlockI9, having less distance to travel than screw 32, will fully drop beforethe screw reaches stop rib I8, thus again limiting closing of thethrottle to the fast-idle position. The unloading. interconnection isalso useful to prevent excessive enrichment or heaviness, as frequentlydiscovered during dynamometer test,- ing, in case the throttle issubstantially opened before the engine vis fully warmed. Y

During the cranking and warm up periods, the thermostatically controlledchoke will act as an air valve, fluctuating under the influence ofvarying suction in the carburetor, this movement being permitted by thelost motion connection between choke lever 25 and link 22, even-thoughblock I9 is held as in Fig. 4. As the thermostat becomes heated, pin 24engages the upper edge 'of slot-23, as shown in Fig. 3, and, if block I9is fast-idle position, asin Figs. 3 and 5. In this position of theparts, .the throttle valve may be fully closed to the normal idlingposition with throttle screw 32 engaging rib I8 (see Fig. 3),

released from screw 32, lifts the block from the and the choke valvewill eventually be moved by the thermostat to its full open position,asin Fig.

5, and will ordinarily remain in this position until the thermostat isagain'closed.

yWhen the throttle is moved to its fully open position, linkage I9, 22will be lifted to its uppermost position, and held in this position dueto engagement between `the lip 2l on block I9 and cam surface 30 on thethrottle lever. As the choke valve is fully opened by the thermostat,finger 29 on choke arm -25 is permitted to pass around nub 21 due tolooseness between slot 23 and pin 24, and the nub is urged outwardlywith respect to pin'24 by spring 29 to insure locking alignment ofelements 26 and 21. Spring 2l also prevents rattling. In the latched orlocked position lof the parts, choke lever 25cannot be rotatedcounterclockwise to close the choke valve as long as linkage I9, 22 isheld in its upper position by the throttle lever Il.; The Vchoke valvewill be locked in this manner,fas distinguished from the partiallyopened unloading position shown in Fig. l, onlywhen the choke has .beenfully opened by the thermostat and the throttle is also fully opened.Thus two different positions of the choke 'are provided in each vofwhich it is locked against closing, both requir'mg substantial openingof the throttle valve, but the throttle valve can force the choke onlyto the4 unloading` position in Fig. l. When lever II is again rotatedclockwise to close the throttle valve after the thermostat is heated,linkage I9, 22 will be supported in its upper 'position by the chokevalve lever. When the-,thermostat cools, the choke can substantiallyfully 'close,'even though block I9 in its descent should `engage theupper edge of screw 32.

t Link 22 is provided with 'a restricted, crimped portion 30 foradjusting the length of the linkage to insure thatefast idle block 4,I9is rendered inoperative at the .proper time relative to the position Vofthe choke valve. Unloading lip 2| is also bend' `of the presentinventor.

connection mechanism, similar in 'some respects to the correspondingparts described above, is disclosed and claimed in copendingapplications, Serial No. 666,118 led April 14, 1933, in the names ofGeorge M. Bicknell and Otto Henning, and Serial No. 89,088, filed July6, 1936, in the name Other features vare claimed in a copendingapplication, Serial No. 666,118, led April 14, v1933, in the names 0fGeorge M. Bicknell and Otto Henning.

'I'he linkage arrangement described is simple and economicaltomanufacture and eiectively modies the functioning of the choke andthrottle valves as required for the fast idle, unloading, and open chokelocking conditions. The carburetor parts shown are not essential andvarious features of the invention may be applied to other types ofcarburetors, whether of the manual or automatic choke variety andwhether having downdraft, updraft, or horizontal mixture passages.Moreover, the interconnecting arrangement itself may be modified invarious respects as will occur to those' skilled in the art and theexclusive use of all such modications as come i within the scope of theappended claims is contemplated.' f v I claim:

1. A link for use in a carburetor having choke and throttle valves, saidlink comprising a sheet metal member having a recess at one end wherebyit may be pivotally connected to an adjacent element and having anopening at .the other end adapted to loosely receive a connecting pin,said link being provided with a pair of slitted and bent portionsbetween said recess and said opening, one

of said portions serving for adjusting the length of said link, and aspring member mounted in the other oi.' said slitted and bent portionsand having one end disposed adjacent said opening for takingy up lostlmotion between said opening and a connecting pin therein.

2. In a carburetor, choke and throttle valves. pivoted control leversfor said valves, interconnection linkage having a pin and slot lostVmotion connection with the choke lever and an abutment structureadjacent said throttle lever for I' engagement thereby when saidthrottle valve isI opened to move said linkage, said choke valve beingcapable of -opening and closing movements independently ol said linkagewhen said throttle valve is opened, said choke lever including a 1at"eral lip spaced outwardlybeyond the pin and slot connection, and saidinterconnecting linkage having an abutment disposed to underlie saidlateral lip when said choke valve is substantially fully opened, and aspring device for causing said linkage to interlock with said chokelevel' when both gagel the otheryof said members, said other memberhaving a portion adapted to be engaged 4by said abutment when bothvalves are open to prevent closing of the choke valve while the throttleremains in open position. f

4. A device of the character described in claim 3 and furtherincluding aconnection operative by the throttle when the choke is in substantiallyclosed position to insure the movement of the choke valve to an onlypartially open position when the throttle valve is completely opened.

5. A device of the character described in claim 3 and furtherincluding amember operable by a full opening movement of the throttle valve forinsuring the opening of said choke valve at least to a predeterminedpartially opened position.

AUGUST H. BLA'ITNER.

